build: Try to work around strict aliasing rules on Ubuntu 10.04

build: Try to work around strict aliasing rules on Ubuntu 10.04

We get cc1: warnings being treated as errors
../lib/util/util_net.c: In function get_socket_port:
../lib/util/util_net.c:921: error: dereferencing pointer sa.106 does break strict-aliasing rules
../lib/util/util_net.c:921: note: initialized from here
../lib/util/util_net.c:925: error: dereferencing pointer sa.107 does break strict-aliasing rules
../lib/util/util_net.c:925: note: initialized from here

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Michael Adam <obnox@samba.org>